Dredging World News Blog

Mine Restores Basin Capacity with Hydraulic Dredge

Posted by Isaiah Helm on Tue, Nov 18, 2014 @ 12:11 PM


SRS Crisafulli introduces the Rotomite model 6000-CD Dredge

SRS Crisafulli designed and built the self-propelled, steerable, diesel powered all-purpose dredge for both abrasive and soft slurries with a cast alloy pump, and 8” discharge, in the fall of 2013.  The dredge was tested at Fisher Sand and Gravel’s pond on Circle Highway northwest of the Company’s Glendive, Montana manufacturing plant, just before winter set in.

 111814First

Photos:  R6CD dredge testing at Fisher Sand and Gravel, Glendive MT, 2013

2014 Job Site

During the winter, the SRS Crisafulli Dredge Sales and Rental Department worked with a copper mine in the American Southwest on a Dredge Rental contract. The mine needed to restore their basin capacity without stopping mine processes, which is the perfect application for hydraulic dredging.

Dredge Application:

Problem: The customer has a plastic-lined tailings dam that collects outflow from various processing facilities. The mixture is generally acidic, with lye added to balance ph levels. A floating pump transfers water and material from this small catch basin into a very large permanent tailings impoundment. The limited ability of the floating pump to pull in slurry led to a build-up of solids, which reduced the pond’s holding capacity.

The customer wanted to restore this capacity to original levels without stopping any mine processes or damaging the liner.

Solution: The new SRS Crisafulli Rotomite model 6000CD was selected for its ability to handle abrasive tailings materials. The Rotomite 6000CD also proved to be well suited for pumping through 500 ft. of 8 in floating discharge pipe, 1500 ft. of 10 inch fused pipe, and over an 80 ft. berm at 1300-1500 gpm. No booster pump was required, reducing cost and complexity of the system. The cutterhead was outfitted with a liner protection cage, preventing its horizontal auger from damaging the liner as it pushed slurry into the pump. This cage restricted the auger from digging into settled solids, so SRS Crisafulli’s unique cutterhead articulation became indispensible as the primary method of breaking up material.

 111814Second

The hydraulic thruster on the back of the Rotomite 6000CD was also a critical component. Both the perimeter and floor of the basin are irregularly shaped, and it is surrounded by a fence, making cable positioning difficult and cumbersome. The thruster’s 180 degree range of motion and hydraulically variable depth allowed quick and easy positioning of the dredge during operation and docking.

The project began with an estimated 76,000 cubic yards of material to be removed.  A satisfactory quantity of tailings was removed to restore the impoundment’s capacity.

Thanks to the SRS Crisafulli dredge rental program, the copper mine’s project was completed in less than six months.

 

The inaugural season of the R6CD was a great success.

Please call the offices to schedule a rental for 2015, or inquire about an equipment purchase.

 

 

Topics: dredging equipment rentals, Hydraulic dredging, Tailings Dam, Rotomite 6000CD

SRS Crisafulli Explores Dredging and Hydropower

Posted by Elizabeth Kaiser on Wed, Jan 25, 2012 @ 08:01 AM

By Elizabeth Kaiser, SRS Crisafulli Marketing Manager

Energy production and consumption worldwide is influenced by many factors.  Resource availability, economic activity, population growth and environmental regulations, for instance, all affect the types of energy production that may be available to consumers.   One of the cheapest methods of energy production is hydroelectric power.

Last spring’s press release by the U.S. Department of the Interior, Departments of Energy and Interior Announce $26.6 Million in Funding to Develop Advanced Hydropower Technologies, announced  “funding for research and development projects to advance hydropower technology, including pumped storage hydropower.”  Hydropower is a sustainable and clean power generating process.  “These funding opportunities will help unlock innovative approaches to hydropower development that emphasize sustainable, clean power generation while reducing environmental impacts.” 

What is the hydropower process?  In short, falling water is passed through a hydroelectric generator to produce electricity. Another hydropower process involves what is called “pumped-storage”. As explained by the Tennessee Valley Authority, “A pumped-storage plant uses two reservoirs, one located at a much higher elevation than the other.  During periods of low demand for electricity, such as nights and weekends, energy is stored by reversing the turbines and pumping water from the lower to the upper reservoir.”

Watch this YouTube video "Hydroelectic Power - How it Works"

 

How is dredging part of this scenario?  The most serious technical problem for hydroelectric dams is accumulation of silt which reduces the water storage capacity of the dam.   Reduced storage capacity limits both electricity generation and the availability of fresh water for downstream uses.  Periodic maintenance dredging removes silt deposits from the dam reservoir and restores water storage capacity, thereby allowing the hydroelectric dam to function more effectively. Periodic dredging can reduce potential negative impacts on fresh water availability without interrupting energy production.

 

Want to learn more about hydroelectric dam dredging?  Contact us.

Watch or download Crisafulli dredge videos.

Subscribe to this blog’s RSS feed for the soon to be announced Rotomite 6000 C Series Dredge.


Topics: Dredges, crisafulli, dredge, dredging, srs crisafulli, dredging abrasive materials, lagoon dredges, dredging system, dredging and pumps, lagoon, rotomite 6000c, Hydraulic dredging

Proactive Dredging: A Little Now or a Lot Later

Posted by Elizabeth Kaiser on Wed, Oct 19, 2011 @ 08:10 AM

By Isaiah Helm, Applications Engineer, SRS Crisafulli

 

If public works departments had a list of fun things to do, dredging sediment out of holding ponds would not be on it.  It’s like cleaning the shower in your bathroom.  Whether you make it a frequent quick job or an occasional laborious task, time and effort must be set aside to maintain a fixture that is as critical as it is uninteresting.  This is the scenario that played out for Georgia’s Cobb County-Marietta Water Authority (CCMWA) during the summer and fall of 2010, as reported in Public Works Magazine

CCMWA had two water treatment plants and a 25 million gallon reservoir in need of upgrade to meet the EPA’s Stage 2 Disinfectant and Disinfection Byproduct Rule of 2006.  During the upgrade, one plant would be running, one shut down.  The reservoir had to be at full capacity to do this.  Unfortunately, it hadn’t been dredged since 1978 and was half full of sludge.  

 proactive dredging resized 600The reservoir was restored to its original 14-foot depth
within six months.  (Photo Credit:  Public Works Magazine)

Timing of all the different upgrade stages coupled with the EPA deadline meant the reservoir had to be cleaned out in six months.  (The dredging had originally been scheduled to take place 2013-2014.) 

In other words, the CCMWA had to make up over 30 years of maintenance in 6 months (that would be one nasty shower!).  The result: increased scale, decreased competition, and ultimately an increased cost.  The amount of dewatering equipment doubled.  Four mobile belt presses and four recessed chamber presses were used.  Fifty trucks made four 45-mile round trips per day.  Bidding on the project was limited to the few large contractors who were even capable of completing the project.  There were five bidders and all five of them listed the same two companies as their subcontractors.  Total cost to dredge the reservoir and perform maintenance on the banks and sluice gates totaled just over $4 million.

The World Dredging Mining & Construction Journal [1] contains a version of the article authored by Steve Gibbs.  It goes on to discuss some observations from the project:

One of the lessons learned by CCMWA is the need for regular dredging of the reservoir.  One benefit of regular dredging is economics – greater capacity in the reservoir reduces the amount of pumping necessary to bring water from the Chattahoochee, thus saving electrical costs.  Also, doing a smaller dredging project every five years or so will eliminate the need to do a massive project such as the one just completed.

A deeper, cleaner reservoir will allow suspended solids to settle out better, which will enhance treatment efficiency.  The reservoir will also have ample capacity while the treatment plants are in their construction phase.

“This (the reservoir dredging project) will decrease the potential for water quality problems or process issues at our treatment plants,” said Ginn (CCMWA process engineer). “It’s a very good proactive preventive maintenance step.”

There you have it.  Proactive dredging of sludge-collecting ponds really does make life easier in the end.  It also increases the options:

  • Put out a request for bids on that smaller dredging project every five years

  • Contract with a dredging company to clean out the pond every five years

  • Rent dredging and dewatering equipment directly and eliminate the middleman

  • Purchase an automated or remote dredging and dewatering system and have it permanently installed for complete self-sufficiency

At least it’s something to think about while you’re cleaning your shower tonight.

 

[1] World Dredging Mining & Construction Journal, “Proper Planning for a Perfect Project” (Volume 46, Nos. 11/12, Page 16)

 

Do you have a proactive dredging project in mind?  Fill out our dredge application form.

Need some advice?  Request a free consultation.

Would you like to receive our monthly newsletter?  Sign me up!

Topics: Dredges, crisafulli, dredge, dredging, srs crisafulli, dredging abrasive materials, lagoon dredges, dredging system, dredging and pumps, dredging equipment rentals, rotomite sd110, lagoon, rotomite 6000c, Hydraulic dredging, rotomite 6000

For $50,000, who wants to be a SRS Crisafulli Millionaire?

Posted by Elizabeth Kaiser on Thu, Jul 14, 2011 @ 13:07 PM

SRS Crisafulli's factory location is intriguing.  SRS Crisafulli is a dredge and pump manufacturer with a factory in land-locked Eastern Montana.  "Glendive, Montana is a unique and very rural community" says SRS Crisafulli President/CFO, Laura M. Fleming. "Glendive is about as far off the beaten track as can be found in modern America. We had two visitors from Israel this week, and sent them home with special stories about Eastern Montana."SRS Crisafulli Factory Employees

"Good People Surrounded by Badlands" is a phrase promoted by the Glendive Chamber of Commerce.  "It was even a $50,000 question on Who Wants to be a Millionaire" adds Ms. Fleming.

"When I present at public speaking events, I use the phrase:  'The River is our Teacher.'  The Yellowstone River and the unique terrain in Eastern Montana created the Company - and vice versa - the people who homesteaded in this area developed unique irrigation methods and technology.  The landscape contributes to the DNA of SRS Crisafulli" says Ms. Fleming.

Photojounalist Lynn Donaldson has visited the Glendive and the SRS Crisafulli factory on several occasions.  "You may visit Lynn's Montana blog at www.placesbetweenspaces.com where you will get a taste of real Montana", says SRS Crisafulli Sales Manager Maureen Lundman.

Yellowstone River at Glendive

The 28 year SRS Crisafulli veteran employee, Ms. Lundman, says "Glendive, our 'City by the Yellowstone', offers unrivalled scenery.  The mighty Yellowstone River bisects the town.  We're always watching the river."

Makoshika State Park

"Glendive is bordered by the rugged and majestic Makoshika State Park. Makoshika (Ma-ko'-shi-ka) is a variant of a Lakota phrase meaning land of bad spirits or badlands."

"Glendive is a warm & welcoming community, and a great place to live--with an excellent school system, a 2-year college, state-of-the-art medical facilities, fantastic hunting, fishing and recreation, as well as a good share of the fine arts available locally."

"SRS Crisafulli employees count themselves as fortunate to live under Montana's Big Sky!" comments Ms. Lundman.  

For additional background about Glendive, please visit:  www.glendivechamber.com

For additional information about Makoshika State Park, please visit:  www.makoshika.org

For a taste of real Montana, please visit Photojournalist Lynn Donaldson's blog:  www.placesbetweenspaces.com

Topics: Dredges, crisafulli, dredge, dredging, marina dredging, srs crisafulli, lagoon dredges, International Exports, Hydraulic dredging

Hydraulic Dredging: A cost effective solution for most dredging tasks

Posted by Dick Memhard on Fri, May 06, 2011 @ 06:05 AM

hydraulic dredging with crisafullis sd110The vast majority of dredging jobs require removal of solids to depths of 30 feet or less. Several features enable hydraulic dredges to be the solution of choice for these applications.

First, what are hydraulic dredges and how do they compare with alternative mechanical dredge types?

Hydraulic dredges create slurries, combinations of solids and water, pump the slurries to the surface of lagoons, ponds, lakes, waterways, and canals, and then pump the slurries through floating and land based pipe to disposal sites. The hydraulic dredging process can be continuous, as contrasted to intermittent in the case of so-called clamshell dredges.

Basic components of hydraulic dredges include a cutterhead, pump, floatation system or platform, engine or motor, control system, and the discharge system. Cutterheads dig up settled solids in the waterway to be dredged and create slurries.  A powerful centrifugal pump mounted directly behind the cutterhead draws the slurry into a discharge piping system, pushes the slurry to the surface, and then to the discharge site, often thousands of feet away from the dredging site. The engine, typically diesel, or electric motor, by means of hydraulic motors and high-pressure hose, transfers the engine’s power to the cutterhead and pump, and in the case of self-propelled dredges, such as SRS Crisafulli’s Rotomite-6000, to the dredge’s propulsion system. Hydraulic dredges integrate the foregoing components into a balanced, highly productive and efficient system.

Hydraulic dredges are made in several configurations, all of which except for cutter/suction and spud dredges, and dredges that require a support vessel, are made by SRS Crisafulli:

  • Horizontal auger hydraulic dredges
  • Suction dredges that have no auger
  • Free standing, self-propelled, steerable dredges with one or more onboard operators
  • Remote controlled dredges typically controlled by a cable system within a well-defined area
  • Dredges with varying degrees of automation
  • Dredges that can operate safely in highly caustic applications
  • Dredges that operate efficiently without a support vessel, or dredges that require a support vessel
  • Cutter/suction dredges
  • Dredges that are positioned with spuds (long, powerful spikes driven into the bottom of the waterway) and use hydraulic rams to apply forward force to the cutterhead
  • Hydraulic dredges are defined also by the depths to which they can dredge, the volume of water and/or solid material they move, the height to which they can discharge the slurry, the power of the auger (or cutterhead), the hardness and abrasiveness of the slurry, the size of solids the dredge pump can pass, dredging speed, width of dredging cut, the cutting power (torque) of the auger, and the cost of the dredge.

The foregoing features all contribute to and determine the productivity of the dredge and the owner’s Return On Investment (ROI) – i.e., how much work the dredge can do in relation to the initial cost of the dredge and the ongoing operating, repair and maintenance expenses of the dredge.

Other types of dredges and solids removal systems are classified as mechanical and include:

  • Clamshell dredges that typically must be operated with a crane
  • Huge, ocean going vessels that can dredge huge volumes at great depths
  • Drag lines that haul a large shovel through the area to be dredged

Each of the foregoing three dredge types provide advantages and disadvantages, including:

  • With the possible exception of draglines, these systems are far more expensive to buy and operate than horizontal hydraulic dredges. For example, horizontal auger hydraulic dredges vary in cost from approximately $150,000 to $700,000. SRS Crisafulli’s most expensive horizontal auger hydraulic dredge can be purchased new in 2011 for approximately $350,000 plus the cost of accessories, spare parts, and options. A high capacity cutter/suction dredge can cost upwards of $1.5 million. An ocean going dredge can cost several million dollars.
  • For the vast majority of applications these three alternative mechanical systems are “over kill”.
  • Clamshell/crane dredging systems together with the large barges the systems are operated on can dredge to greater depths, and dispose of the dredged materials many miles away at dumpsites approved by the EPA. But these systems are bulky, noisy, and more costly to buy and operate.

Selecting the best dredge solution for any application requires careful analysis by experienced, well-trained people in collaboration with the customer’s staff. Frequently, such an analysis requires the efforts of engineers with the skills and experience to sort out the many variables.

What would you like to do now?

  1. Request a dredge application form?
  2. Download the SRS Crisafulli product information DVD?
  3. Speak to one of our qualified technicians about your specific dredging requirements?

Topics: Dredges, crisafulli, dredge, srs crisafulli, Hydraulic dredging